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 Advances in dental technology have now made it possible to create posterior crowns and bridges in ceramic or polyceramic material without any metal coping. This is a case report by Dr. Anupama Patil on the restoration of a badly broken down upper second molar. CASE STUDY:METAL- FREE FULL CROWN PROSTHESIS.The restoration of teeth, carious to an extent that a filling will not hold itself, is commonly accomplished through the fabrication of full crown prosthesis. Traditionally either a full metal crown is used, or a metal substrate is veneered/surfaced with a ceramic agent for the purpose of enhancing the aesthetic appearance. In modern times bonding has been more or less universally accepted by one and all. This has lead to attempts to replace the brittle ceramic component with various types of polymer and polyceramic based materials. These restoration systems provide very high level aesthetics with biocompatibility in the oral cavity. An added advantage is antagonistic enamel wear similar to that of resin material unlike ceramics which cause extensive abrasion of the occluding antagonist teeth. Coupled with the fact that these materials also offer a high wear resistance the use of such materials becomes very exciting. One such material, which is distinctive in this new metal-free range of materials is Sculpture. SCULPTURE :Sculpture/FibreKor is a two- component polymer restorative system manufactured by Jeneric/ Pentron Company. Of these two components in the entire system, the Sculpture component is a light and heat – polymerizable particulate hybrid composite called as "polyceram". The basic components are the filler particles and the interparticulate matrix. The matrix is the resin Polycarboxylate dimetharcylate (PCDMA). This resin results in high fracture toughness and lower polymerization shrinkage (1/6 to 1/15 of porcelains by volume). In other words it consists of about 80% of ceramic filler and 20% of resin matrix. Sculpture is mainly indicated to fabricate inlays, onlays, crowns and veneers, when it is not used in conjunction with the fiber component. When used in combination with the Fibrekor component the entire system can be used to fabricate regular abutment supported fixed prosthesis. Sculpture has the following properties:
Sculpture truly challenges the aesthetics of porcelain while offering user-friendly handling, excellent marginal integrity, polishability and substantially increased productivity. The added advantage is that the system provides one with the entire range of shades according to the Vita- shade guide, with additional colour modifiers, neck pastes, incisal shades, gingival shades and stains for the grooves, giving one flexibility of producing desired aesthetic results. CLINICAL CASE STUDY:
Root Canal Treatment: The root canal treatment was done in one sitting. The pulp chamber was opened so as to get a direct view of the orifices of the canals. The pulp tissue was extirpated using the crown down technique with the automated endodontic system. This comprises of the Fine Cut Handpiece and the Fine Cut Files (with a positive rake angle). The handpiece allows up & down movement of the file, which is held in the slot of the head of the handpiece, enabling one to do circumferential filing as one holds the file against the canal walls, moving along the circumference of the orifice . The washed filed technique is used which entails using the largest possible file fitting loosely in the canal ensuring that the biomechanical preparation is done without causing any apical inoculation. Next a file was dropped in each canal and a diagnostic x-ray taken. The canal lengths then were adjusted according to the x-ray. Using a digital vernier caliper, which measures up to 1/100th of a mm, the final lengths were achieved which are accurate up to 5/10th of a mm, taking into account the x-ray distortion. The lengths were MB- 22.00mm, DB-22.63mm and P- 19.23mm. The biomechanical preparation was then completed so as to get a needle seat 1 mm short. The obturation was done with endodontic cement using a multi-mode precision syringe. The endodontic cement is a root canal sealer, which is ADA approved cement , to be used as a sealer and filler in root canals. The patient was given an IMR and scheduled for the next appointment. Preparation Design and Impresions : In the next sitting the tooth was assessed for restoration of the remaining tooth structure. The tooth destruction was way beyond the limits of a direct composite restoration. Hence, a full crown restoration was mandatory. The remaining tooth structure had a number of undercuts. The pulp chamber and the undercuts were blocked out with light cured composite and then the crown preparation was carried out.
The shade was selected using the vita shade guide - A4, A3 with an orange halo and clear incisal shade. A provisional restoration was not made since; the patient was scheduled for crown fitting within a day after the impressions were recorded. Fabrication of the Crown : The crown was fabricated in the in-house lab at Sanjeevni Dental Clinic. The entire process takes approximately an hour and half. The models were then poured in diestone. The crown was prepared using the Sculpture/ Fibre-Kor unit provided by the company. The fabrication includes a number of steps
Try In : In the next appointment the crown was tried in the patients mouth. The aesthetic blend with the adjacent tooth was perfect. The marginal integrity was checked by running a probe from the tooth surface on to the crown. The contact was found to be slightly open. This was built up and tried again immediately. Once a proper contact was established, the occlusion was adjusted using an ultra thin marking paper. The high points were polished off with a carbide-finishing bur taking care to maintain the anatomy. Finishing and Polishing : The final finishing and polishing was carried out once a perfect fit was obtained and the patient found the prosthesis very comfortable in occlusion. This step consisted of a series of finishing burs from coarse to the fine variety. Routinely the carbide-finishing bur is enough to give the rough finish. This was followed by a set of porcelain finishing wheels (again coarse to fine), of the company, using a micro motor. Next, the crown was polished using #9 and #11 bristle brush wheels which are supplied with the Sculpture polishing paste. This results in a highly polished surface as can be seen in the final finished crown. In the entire process utmost care was taken to retain the sculpted anatomy as natural as possible. Placement Technique : Placement technique involves preparation of the tooth surface and the underside of the prosthesis. The prosthesis was put in an ultrasonic cleanser for 30 seconds to remove any residual particulate debris on the bonding surface. It was then rinsed and dried thoroughly. The inner surface was microetched using a sand blaster. The surface was again thoroughly air dried to remove the sand particles. A thin coat of Silane was then applied on this microetched surface. After a minute of waiting to let the Silane dry, a layer of bond was applied. The prosthesis was now ready for final fitting. A diamond bur was run on the tooth surface to create a fresh layer of dentine, devoid of the slime layer, which had accumulated over the last few hours. A retraction cord was put into the sulcus. The area was completely isolated. Next the surfaced was etched for 10 seconds with an etching gel. After rinsing off the gel, a layer of primer and bond was applied to the surface. It was allowed to soak into the dentine for 15 seconds and then air dried for 15 seconds with a steady gentle stream of air with a three-way syringe. This was then light cured for 20 seconds. The presence of a shining surface indicates the proper application of the primer and bond layer. Next, adequate amount of luting cement was dispensed out on mixing pad. The luting cement used was a resin based cement of the dual-cure variety. The cement was mixed, loaded on the crown and the crown gently pressed on the prepared tooth surface. With the crown held in place, the excess was removed. The retraction cord was then removed and the excess cement interdentally removed with a probe. This was cured holding the crown firmly in place. The margins were finished using fine finishing burs. The bite was once again checked, using marking ribbon. The high points were adjusted and then a good polish achieved with regular composite finishing kit. Care was taken so that only the high point areas were finished without compromising the finish of the entire crown achieved during the laboratory procedure. Final Result : The restorative material will not cause accelerated wear of the opposing natural teeth. Besides the excellent marginal integrity lowers the chances of secondary decay, as there is no marginal over hang and is accessible for the patient to maintain proper hygiene. The contact area between adjacent teeth are maintained as natural as possible lessening the chances of interdental food impaction due to bad contact areas. The crown is not bulbous ensuring the chewing' comfort of the patient and not cause traumatic cheek bite. The use of Sculpture as the anatomical form of the restoration offers high resistance and its low potential for abrading the antagonist tooth structure makes the material preferable to conventional ceramic systems.
CONCLUSION: With the introduction of reinforced polymer glass (composite resin), we can now provide our patients with aesthetics and function and replace missing teeth without wear of opposing natural teeth or other restorative materials. Though the material has been available for a short time, we can extrapolate from the success of other uses of processed composite and feel confident that we can offer long-lasting restorations that give the patient conservative alternatives to traditional restorative options. As with any new restorative system, longitudinal clinical studies and in vivo evaluations are required to substantiate the favorable initial results. | |
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A male patient of age 55 years, reported with a
complaint of continuous pain in the upper right posterior region. The pain
would aggravate in night and on lying down. On examination it was seen
that the upper right second molar was badly carious. The molar gave a
positive response on percussion (pop +ve). It showed presence of a small
carious lesion on the mesial marginal ridge. On removal of caries using a
caries indicator, under infiltration of local anesthesia, a small carious
pulpal exposure was seen. This required the need for Endodontic
intervention.
The crown preparation essentially follows
the "all ceramic doctrine". Circumferential reduction with
a 1.5 mm rounded shoulder preparation, following the contour of the
gingival crest, was made. The cavosurface margin of the shoulder was
90 degrees with no chamfer or bevel. Axiogingival line angles were
rounded internally, and axial walls had a 10-15 degree taper towards
the long axis of the tooth. Occlusal reduction of 2mm was done
maintaining a proper cuspal inclination. All occluso-axial line
angles were rounded and smooth. To maintain a passive path of insertion,
The preparation was made devoid of any undercuts.
A knitted non- impregnated retraction cord was
selected; the size corresponding to the sulcus depth .The retraction
cord was then soaked in Astringendent and inserted in the sulcus. Upper
and lower impression trays were selected. Then upper arch rubber base
impression was taken with the two-step impression technique. The upper
arch putty impression was made with the polythene spacer placed on the
tray. The retraction cord was removed just before the wash impression was made. Once this
was set the wash impression was made after removing the spacer. The
lower arch impression was made in sodium alginate. 
